1 // SPDX-License-Identifier: GPL-2.0-only 2 #include <linux/module.h> 3 4 #include <linux/mm.h> /* for handle_mm_fault() */ 5 #include <linux/ftrace.h> 6 #include <linux/sched/stat.h> 7 #include <asm/asm-offsets.h> 8 9 extern void my_direct_func(unsigned long ip); 10 11 void my_direct_func(unsigned long ip) 12 { 13 trace_printk("ip %lx\n", ip); 14 } 15 16 extern void my_tramp(void *); 17 18 #ifdef CONFIG_X86_64 19 20 #include <asm/ibt.h> 21 #include <asm/nospec-branch.h> 22 23 asm ( 24 " .pushsection .text, \"ax\", @progbits\n" 25 " .type my_tramp, @function\n" 26 " .globl my_tramp\n" 27 " my_tramp:" 28 ASM_ENDBR 29 " pushq %rbp\n" 30 " movq %rsp, %rbp\n" 31 CALL_DEPTH_ACCOUNT 32 " pushq %rdi\n" 33 " movq 8(%rbp), %rdi\n" 34 " call my_direct_func\n" 35 " popq %rdi\n" 36 " leave\n" 37 ASM_RET 38 " .size my_tramp, .-my_tramp\n" 39 " .popsection\n" 40 ); 41 42 #endif /* CONFIG_X86_64 */ 43 44 #ifdef CONFIG_S390 45 46 asm ( 47 " .pushsection .text, \"ax\", @progbits\n" 48 " .type my_tramp, @function\n" 49 " .globl my_tramp\n" 50 " my_tramp:" 51 " lgr %r1,%r15\n" 52 " stmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n" 53 " stg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n" 54 " aghi %r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n" 55 " stg %r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n" 56 " lgr %r2,%r0\n" 57 " brasl %r14,my_direct_func\n" 58 " aghi %r15,"__stringify(STACK_FRAME_OVERHEAD)"\n" 59 " lmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n" 60 " lg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n" 61 " lgr %r1,%r0\n" 62 " br %r1\n" 63 " .size my_tramp, .-my_tramp\n" 64 " .popsection\n" 65 ); 66 67 #endif /* CONFIG_S390 */ 68 69 static struct ftrace_ops direct; 70 71 static int __init ftrace_direct_multi_init(void) 72 { 73 ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0); 74 ftrace_set_filter_ip(&direct, (unsigned long) schedule, 0, 0); 75 76 return register_ftrace_direct_multi(&direct, (unsigned long) my_tramp); 77 } 78 79 static void __exit ftrace_direct_multi_exit(void) 80 { 81 unregister_ftrace_direct_multi(&direct, (unsigned long) my_tramp); 82 ftrace_free_filter(&direct); 83 } 84 85 module_init(ftrace_direct_multi_init); 86 module_exit(ftrace_direct_multi_exit); 87 88 MODULE_AUTHOR("Jiri Olsa"); 89 MODULE_DESCRIPTION("Example use case of using register_ftrace_direct_multi()"); 90 MODULE_LICENSE("GPL"); 91